KR20080075140A - Reclaiming substrates having defects and contaminants - Google Patents

Abstract

Test substrates used to test semiconductor fabrication tools are reclaimed by reading from a database the process steps performed on each test substrate and selecting a reclamation process from a plurality of reclamation processes. The reclamation process can include crystal lattice defect or metallic contaminant reduction treatments for reclaiming each test substrate. Each test substrate is sorted and placed into a group of test substrates having a common defect or contaminant reduction treatment assigned to the test substrates of the group. Additional features are described and claimed.

Description

Recycling substrates with defects and contaminants {RECLAIMING SUBSTRATES HAVING DEFECTS AND CONTAMINANTS}

Embodiments of the invention relate to reclaiming of substrates in semiconductor fabrication.

In manufacturing electronic devices, various materials may be deposited on a substrate, such as a semiconductor substrate or display, or sequentially etched from the substrate to form features such as interconnect lines. Such materials may include metal-containing materials such as, for example, aluminum, copper, tantalum, tungsten and compounds thereof. Other materials deposited on the substrates include silicon and various oxides and other nonmetal materials. Such materials may be deposited using sputtering (also referred to as physical vapor deposition or PVD), chemical vapor deposition (CVD), and thermal growth. In addition to the deposition of materials, other fabrication processes may be performed including doping, diffusion, ion implantation, etching, chemical and mechanical polishing (CMP), cleaning and thermal treatments of semiconductor layers through impurities.

In such fabrication processes, test substrates are often used to test whether the fabrication process is operating in specification. For example, to test a copper sputtering process, a test substrate can be placed in a copper sputtering tool and copper sputter deposited on the test substrate. The test substrate can then be inspected to verify whether the final deposited copper layer is within the performance conditions. If not within the performance conditions, the controls for the copper sputtering tool can be adjusted and the tool can be tested again through the same or another test substrate until the desired copper deposition layer is reliably achieved.

Regeneration of substrates, used to test or monitor processes through constant pressure to reduce costs, or fall short of deposition or etching process criteria or for other reasons, is a good alternative to the purchase of new substrates. Rather than simply discarding the substrates, it is more cost effective to recycle the used test substrates. The regeneration process typically involves removing all deposited layers and materials and removing a portion of the underlying silicon material, such that the remaining silicon material of the test substrate is cleaned and substantially no added materials or other contaminants remain. . As a result, the regeneration process is intended to recover the test substrate to meet the same performance conditions as the new test substrate except for its thickness. For example, it is often desirable to regenerate test substrates with contaminants. Regeneration processes often have unique requirements when the contaminants include metallic species such as metal elements or metal compounds. To prevent contamination, it is often desirable for test substrates deposited on top of metallic paper to be recycled separately from other test substrates, with or without metallic deposits.

As technology advances, more devices are fabricated using copper interconnects and lines, and substrates contaminated by copper-containing species such as copper elements or copper compounds often need to be recycled separately from other substrates. There is. Copper from copper-containing substrates can easily contaminate other substrates when copper-containing substrates are used to recycle other substrates or when recycled in the same bath, through the use of recycle polishing slurry. . Moreover, tests for contamination of the substrate surface using ICP-MS (inductively coupled plasma mass spectroscopy) do not detect copper diffused from the surface into the bulk of the silicon substrate. This may result in shipping the substrates to customers with high levels of copper contamination in the bulk of the substrate. Subsequently, long storage cycles or increased temperatures and warehouse conditions during transport can cause copper to diffuse from the bulk to the surface, which negatively affects the devices formed in the substrate.

One process for removing metallic contaminants such as copper is described in US Pat. No. 6,054,373 entitled "Methods of and Apparatus for Removing Metallic Impurities Defused in a Semiconductor Substrate" issued April 25, 2005, It is hereby incorporated by reference in its entirety. This patent describes a process in which a substrate is heated in-situ in an acid bath of sulfuric acid. However, after removing the copper contaminants from the batch of substrates, the final chemical bath contains high levels of copper contaminants that can be diffused into the substrates and then sequentially dipped into the bath. When a second substrate comprising a low level of surface contamination is treated after a first substrate having a high level of surface contamination, cross-contamination is particularly problematic, in which case copper from the first substrate is often the second substrate. Further contaminate.

In order to separate the substrates prior to regeneration, test substrates used for regeneration are often classified into one of several regeneration categories and then stored in cassettes. Notes may be noted on each cassette label indicating a particular category (such as “lattice defect type”, “copper”, “metal” or “non-metal”) that the test substrates of the cassette belong to. The test substrates may then be transferred to an in-house regeneration service operator or shipped to an external service provider. Test substrates are often shipped or shipped in bulk, ie hundreds or thousands at the same time. The playback service operator, upon receipt of the test substrates, obtains a note of any notifications recorded on the cassette labels, removes the test substrates from the cassettes, visually inspects the test substrates, and is typically "copper", "metal". Categorize them again into regeneration categories, such as the "or" non-metal "categories. Then, the test substrates of each category are processed using a regeneration process suitable for that particular category.

By reading the process steps performed on each of the plurality of test substrates from a database and selecting a specific regeneration process for each test substrate, one system in which the test substrates are regenerated is filed on October 11, 2005 and the applicant of the present application. US Patent No. 6,954,722, entitled "TEST SUBSTRATE RECLAMATION METHOD AND APPARATUS," which is hereby incorporated by reference in its entirety. For example, the process steps performed here on test substrates include material deposition; The data read from the database may include data in the process step indicating the type of deposited material and the thickness of the deposited material. Then, a regeneration process suitable for the test substrate may be selected for each test substrate depending on the type of materials deposited on the test substrate and the respective deposition thickness. Regeneration processes may be selected based on ion implantation, CMP, cleaning, thermal treatments and etching, and other processes performed on test substrates, including details related to those processes. The information identifier for each test substrate, the processes performed on the test substrate, and the regeneration process selected for the test substrate can be stored in the test substrate history database.

In addition, each test substrate for which a regeneration process is selected may be classified and placed into a group of test substrates having a common regeneration process assigned to a group of test substrates. For example, test boards may be sorted in an automated system in which an identification code is read from each test board by a scanner or other suitable reader, and the playback process assigned to the test board is read from a database, and the same or similar playback process The test substrate is placed by a robot or other automated substrate handlers in another bin or cassette that contains additional test substrates assigned thereto.

In addition, the reservoirs in which the sorted test substrates are stored may be labeled with identification information including basic information or detailed information on the selected regeneration process for the test substrates stored in the reservoir. The information may also include a list of test substrates stored in each reservoir. The information identifier for each reservoir, the test substrates stored in the reservoir, and the playback process selected for those test substrates may be stored in a database for that reservoir.

The sorted test substrates may be removed from the reservoirs by the replay operator of the automated system where an identification code is read from each test substrate by a suitable reader. The regeneration process assigned to the test substrate may be read from a database provided to the operator to verify which regeneration process has been assigned to each test substrate prior to regeneration of the test substrate.

Test substrates used to test semiconductor fabrication tools are sorted for regenerating substrates. As one method, a plurality of test substrate identification data is read from the plurality of test substrates. For each read test substrate, stored test substrate data describing the read test substrate is obtained from a database. Each read test substrate is assigned a crystal lattice defect reduction process associated with the stored test substrate data for the read test substrate.

A system is provided for regenerating test substrates each having an identification code. The system includes a reader and a controller for reading the identification code from the test substrate. The controller has a memory for storing a database containing data indicative of an identification code for each test substrate and associated data indicative of crystal lattice defect reduction processing. The controller also obtains, from the database for each read test substrate, stored test substrate data describing each read test substrate, and performs crystal lattice defect reduction processing associated with the stored test substrate data for the read test substrate. Program code for assignment to a read test substrate.

An article of manufacture for regenerating test substrates used to test semiconductor manufacturing tools is disclosed. The article of manufacture enables the controller to (a) store a plurality of test substrate identification data in a database, where each test substrate identification data identifies a particular test substrate of the plurality of test substrates; (b) make it possible to select a crystal lattice defect reduction process from a plurality of crystal lattice defect reduction processes to reproduce each of the plurality of test substrates identified by the plurality of test substrate identification data; And (c) store, in a database, a plurality of test substrate crystal lattice defect reduction process identification data associated with the stored test substrate identification data to identify a playback process selected for reproducing the test substrate. Contains program code.

A computer readable medium is provided that includes a computer database of data for reproducing test substrates used to test a semiconductor manufacturing tool. The computer readable medium includes a plurality of test substrate identification data, each test substrate identification data identifying a particular test substrate of the plurality of test substrates. Each crystal lattice defect reduction process data of the plurality of crystal lattice defect reduction process data is associated with test substrate identification data.

A method of regenerating test substrates used to test semiconductor manufacturing tools includes reading a plurality of test substrate identification data from a plurality of test substrates; For each read test substrate, obtaining stored test substrate data describing each read test substrate from a database; And assigning each read test substrate a metal contamination reduction process associated with the stored test substrate data for each read test substrate.

A method of regenerating test substrates used to test semiconductor manufacturing tools,

(a) reading a plurality of test substrate identification data from the plurality of test substrates;

(b) for each read test substrate, obtaining stored test substrate data describing each read test substrate from a database; And

(c) assigning each read test substrate a copper contaminant reduction process as a function of the stored test substrate data for each read test substrate.

The method of regenerating substrates includes providing a substrate comprising metallic contaminants at a first surface concentration level. The substrate is heated such that bulk metallic contaminants of the substrate diffuse to the surface of the substrate. Thereafter, the substrate is quenched at a quench rate high enough to obtain a second surface concentration level of metallic contaminants at least about 20% higher than the first surface concentration level after quenching. The substrate can be heated, for example, in a heated furnace or by applying microwave light to the substrate. The method may also be used to inspect and detect increased surface concentration levels of metallic contaminants of the substrate.

These features, embodiments, and advantages of the present invention will be better understood with reference to the following detailed description, the appended claims, and the accompanying drawings, which illustrate examples of the invention. However, it should be understood that each feature may be used in the present invention in its entirety rather than only in the scope of the specific figures, and that the present invention includes any combination of these features.

1 is a conceptual diagram of an illustrative example of a playback and classification system.

2 is a flowchart showing an example of a reproduction preparation process.

3 is a conceptual diagram of an example of a playback cassette database.

4 is a conceptual diagram of an example of a test substrate history and inspection database.

5 is a conceptual diagram of an example of a test substrate sorting apparatus.

6 shows examples of playback cassettes with an attached printing label.

7 is a flow diagram illustrating an example of operations used to map test substrates and cassettes and inspect test substrates.

8 is an example of a report on test substrates and cassettes.

9 is a flow diagram illustrating an example of operations for generating a test substrate history and inspection database.

10 is a flowchart illustrating an example of operations of a playback algorithm engine.

11 is a flow diagram illustrating an example of the operations of a process of classifying test substrates by regeneration category.

12 is an example of a playback cassette label.

13 is a flowchart illustrating an example of a playback process.

14 is a conceptual diagram of an example of a database.

FIG. 15 is a flow diagram illustrating an example of operations by a playback supplier to verify a test board ID, cassette ID, and playback categories. FIG.

16 shows an example of identification codes disposed on a test substrate.

17 shows an example of an identification code for a test substrate that reflects the processing history of the test substrate.

18 is a block diagram of a controller suitable for the system of the present invention.

1 illustrates an example of a computer system 100 that is determined to significantly improve the reproduction of substrates, such as test substrates used and other substrates used in the manufacture of semiconductor devices and displays. System 100 is used in the playback preparation process as an example summarized in FIG. For example, system 100 can be used to facilitate the regeneration of test substrates with crystal lattice defects or metallic contaminants; Certain such defects and contaminants occur near the substrate surface. In one embodiment, test substrates may be identified and classified into groups that are assumed to have one or more types of defects or contaminants, or are likely to have minimum levels of defects or contaminants. For example, test substrates identified as coming from the same ingot section may be considered to have crystal lattice defects, and other test substrates made from the same ingot section are determined to have crystal lattice defects. . In addition, test substrates may be classified into groups considered to be likely to have crystal lattice defects as a result of performing a common processing step, such as a high temperature annealing process determined to be capable of inducing or deepening crystal lattice defects. Similarly, substrates that have performed metal deposition processes may have higher levels of metal contaminants.

In another embodiment, the input test substrates are placed in an in-line sensor that includes an automated or semi-automated inspection facility capable of detecting the presence of crystal lattice defects, metal contaminants, or other levels. Can be checked by Such test substrates determined to be likely to have crystal lattice defects can be classified into groups, each group being assigned a common common lattice defect reduction treatment appropriate for the group's identified crystal lattice defects, and metal contaminants. The same is true for the field.

In the example of the regeneration preparation process 110, the test substrates to be regenerated are identified by the system 100 (block 112), stored in the cassettes 118, and each cassette may contain alphanumeric or other symbols. Preferably, a unique identification code is assigned. While the illustrated system is described in conjunction with silicon test substrates and cassettes, certain embodiments include other types of test semiconductors, including silicon on insulators (SOI), gallium arsenide, germanium, silicon germanium, glass, and other test substrates. And non-semiconductor substrates. In addition, it is contemplated that storage containers or reservoirs may be used in addition to the cassette. One example is a FOUP used to transport 300 mm substrates.

3 is a conceptual diagram illustrating an example of a computer database 120 in which the system 100 stores an identification code of each test substrate to be reproduced, and an identification code of a specific cassette 118 in which each such test substrate is stored. to be. System 100 includes a controller 300 that includes a suitable computer or computer network 124 (FIG. 1) that maintains a cassette database 120. The reader 126 reads an identification code from each test substrate 130 to be reproduced for storage in the database 120.

According to another embodiment of the shown regeneration process 110, the system 100 may extract substrate source history data, including the ingot and the section of the ingot from which the test substrate was made (block 132 of FIG. 2). . The extracted substrate data may include a processing history of each test substrate to be reproduced. This processing history may include data describing the various layers (if any) deposited on the test substrate, and data describing other processes performed on the test substrates, including annealing, etching, cleaning, polishing, and the like. Silicon ingot manufacturers frequently maintain databases that track each substrate from the source ingot and the section of the ingot making the substrate.

In addition, the processes performed on each substrate that pass through a manufacturing system, such as an integrated circuit manufacturing plant, are tracked. Thus, such source and processing history data are extracted from the databases pre-existed by the system 100 and generated by the system 100 for each test substrate identified to prepare for playback (FIG. 2). Block 140) may be stored (block 132) in the test substrate history and inspection database. 4 shows an example of a test history and inspection database 150 in which the source of each test substrate and each processing step performed on the test substrate are stored in association with an identification code of a particular test substrate.

In another embodiment, each test substrate to be regenerated may be inspected for crystal lattice defects (block 142). Such inspection may be performed manually or by a suitable automated inspection facility, such as in-line optics or X-ray sensor 136 (FIG. 1) of system 100. The inspection results may be stored in the test substrate history and inspection database (block 144) generated by the system 100 (block 140 in FIG. 2) for each identified test substrate in preparation for regeneration.

Using the test substrate history database 150, the system 100 can examine the source data of each test substrate, the processing steps performed on a particular test substrate, and inspection results for each test substrate (FIG. Block 154 of 2), appropriate crystal lattice defects or metallic contaminant reduction treatment can determine which of a number of methods for regenerating a particular test substrate is appropriate. For example, if a test substrate was obtained from a particular section of a particular ingot that produced substrates with crystal lattice defects, it may be determined that the test substrate is likely to have similar crystal lattice defects. Thus, an appropriate crystal lattice defect reduction process can be assigned to the test substrate.

As another example, the test substrate processing history may indicate that the test substrate has performed high temperature annealing at the manufacturing facility. Moreover, the annealing process can be of a type that induces or deepens crystal lattice defects. Again, an appropriate crystal lattice defect reduction process can be assigned to the test substrate.

As another example, the inspection results may indicate a high likelihood of crystal lattice defects of that particular test substrate. Some inspection instruments consider that surface particles and crystal lattice defects cannot be easily distinguished. In addition, some preprocessing operations, such as film deposition, can cover defects, especially for optical sensors. Thus, in some applications, the inspection may be performed after deposit removal, cleaning or polishing has already been performed in the entire regeneration process to facilitate the inspection process. Other inspection sensors, such as X-ray devices, may be suitable for detecting crystal lattice defects before the actual regeneration process begins, such as before removal, cleaning, polishing, etc. of deposited films. However, in some applications, it may be appropriate to remove metal deposits prior to X-rays of the test substrate.

As another example, inspection results may indicate a high likelihood of metallic contaminants of a particular test substrate. For example, a test substrate processing history may indicate that the test substrate has performed a metallic material deposition process, and / or high temperature annealing after deposition. For example, appropriate metal contaminant defect reduction treatment, such as copper defect reduction treatment for copper contaminant substrates, may be assigned to the test substrate.

It is contemplated that the test substrates can be reproduced more efficiently by utilizing a database such as test substrate history and inspection database 150 to select a regeneration method that is particularly suitable for a particular test substrate. In the illustrated embodiment, the system 100 includes a regeneration algorithm engine that identifies a method for reproducing each test substrate based on detailed source and processing history and test results for the test substrate, The identifying data is stored in one or more databases 120, 150 of system 100.

Once the appropriate regeneration methods have been identified for one or more test substrates, the information can be used by the system 100 to classify the test substrates into various categories based on the method selected for each test substrate ( Block 160 of FIG. 2. 5 shows an example of a robotic system 170 of system 100, from which any number of storage cassettes or other storage bins 118a, 118b, 118c... ) Can be removed and the test substrate can be stored in any other storage cassettes 118a, 118b, 118c... 118n. In the illustrated embodiment, a reader 126a, 126b… 126n, such as an optical scanner or other type, is positioned adjacent to one or more reservoirs to verify the test board identification code of the test board being handled by the robot 172. In order for the test substrate to be extracted from the cassette to be interlocked or inserted into the cassette to be interlocked, the test substrate can be scanned.

In addition, the system 170 may include an inline sensor 136 for performing inspections of the substrates 130 for crystal lattice defects or metal contaminants as the test substrate is handled by the robot 172. have. Such checks may be performed as test substrates are identified for regeneration after all regeneration steps have been performed, or during the regeneration process, except for any defect or contaminant reduction treatment that may subsequently be assigned.

As an example, all test substrates to which one particular reproducing method or category has been assigned may be stored in one cassette up to the capacity of the cassette. System 100 includes a printer 180 (FIG. 1) for printing a label 182a ... 182n (FIG. 6) for each cassette 118a, 118n, respectively. Each label may be attached to an associated cassette, identified by identification codes, and each test substrate is stored in the cassette by the robot classification system 170, as described below with the replay algorithm engine and as described below. By the same other information, a specific reproduction method is selected for each test substrates of the cassette. Then, the test substrates of each cassette are waited to proceed with the reproduction, using the reproduction process identified by the label attached to the cassette storing the test substrates (block 190 in FIG. 2). The regeneration process may include or constitute one or more suitable crystal lattice defect or metallic contaminant reduction treatments.

7 illustrates in more detail an example of the test substrates to be reproduced and the operations 19 that may be performed to identify (block 112 of FIG. 2) and inspect (block 142) stored test substrates. Once a new cassette of test substrates is identified (block 200), the cassette is assigned a unique cassette identification code (block 202) and a new record is created in the cassette database 120 (block 204). As shown in Fig. 3, the cassette database 120 has recording sections 210a ... 210n for each cassette 118a ... 118n, respectively. Each record has a field 212 in which a cassette identification code is stored (block 220 in FIG. 7). In the embodiment shown, the cassette identification code may be a series of symbols including alphanumeric characters and any other symbols that uniquely identify a particular cassette.

If a record is created in the cassette database 120 for the cassette being processed and the identification code of the cassette is stored in the appropriate field 212, or if the cassette already has an associated record of the cassette database 120 (block 200 The robot 172 removes the test substrate from the cassette (block 230), and the scanner 126 scans the test substrate to read the test substrate identification code (block 232). Like the cassette identification code, the substrate identification code can be a series of symbols including alphanumeric characters and other symbols that uniquely identify a particular test substrate. These test substrate identification codes are often engraved directly on the front or back surfaces of the test substrate using lasers.

16 shows an example of a test board identification code 240 engraved with a laser near the edge 242 of the test board 130. Test substrates often have a notch 244, a flat edge (not shown), or other orientation features to facilitate robot handling. The test board identification code 240 is preferably of a type that can be easily identified by readers 126 such as optical scanners or other reading devices to facilitate automated handling of the substrates.

In addition, the test substrate may be inspected for crystal lattice defects, metallic contaminants, or levels thereof (block 246). Once the identification code of the substrate is read (and the substrate is inspected, if appropriate), the test substrate into the same or another cassette can be replaced (block 250 of FIG. 7). In addition, the test substrate identification code read from the test substrate is stored in the cassette database 120 of the field 262 (FIG. 3) of the record associated with the specific cassette in which the test substrate is placed (block 260). Many cassettes or other storage bins often have slots that support each individual substrate. Such slots are often uniquely identified by individual slot numbers. In this example, each cassette is slot 1, slot 2... It has a number of slots numbered as slot n. Therefore, the slot number, slot 1, slot 2... Slot n may be written to field 264 associated with the identification code of the test substrate stored in that slot (block 260).

Once all test substrates of the cassette being processed have been scanned and inspected (block 270), the preliminary cassette label can be printed by the printer 180 of the system 100 (block 272) and attached to the cassette. This preliminary label may include information such as a cassette identification code and may include a list of substrate identification codes of test substrates stored in the cassette for reproduction. The cassette and test substrate identification process of FIG. 7 may be repeated for all cassettes of test substrates to be regenerated, or in the process being regenerated.

Identification information for all such cassettes and test substrates may be printed in the example report shown in FIG. 8. This report 280 may include a list of cassettes containing test substrates to be reproduced, where each cassette is identified by a unique cassette identification code and a list of test substrates stored in each cassette. The information about each test substrate may include an identification code of the test substrate and a cassette slot number in which the test substrate is stored.

FIG. 9 illustrates in more detail an example of operations 290 that may be performed to generate a test substrate history and inspection database, such as database 150 shown in FIG. 4 (block 140 of FIG. 2). 9 are preferably performed after one or more test substrates have been identified and inspected in a manner similar to that described above in connection with FIG. Thus, the test substrate history data may be stored in the test substrate history and inspection database 150 after each test substrate is identified by the reader and inspected by the inspection apparatus, or alternatively a batch of test substrates may be for example. After identified by the operations of FIG. 7, data may be stored in a test substrate history database for a batch of test substrates.

In order to add the test board history data to the test board database 150, a record such as record 300a (FIG. 4) is created for the individual test board (block 302 in FIG. 9), and an identification code for a specific test board. Is stored in field 306 (block 304). If historical data and / or test result data are available for the test substrate (block 310), the substrate data is stored in the recorder 300 describing the source of the substrate and / or one or more processes performed on the test substrate (block 312). In the example of Figures 4 and 9, it is preferred that data is stored for each manufacturing-processing step performed on the test substrate. Such data may include a step number for each processing step, which is stored in field 314 to indicate the chronological order in which the various processing steps were performed on the test substrate. In addition, data identifying the type of process performed in each step may be stored, for example, in field 316. The various processes identified for a particular processing step may include, for example, annealing, CVD, PVD, thermal growth, doping, diffusion, ion implantation, etching, CMP, cleaning, defect inspection, and the like. In addition, for each processing type, additional data may be stored in various fields. For example, for the annealing step, a temperature ramp rate may be stored in field 320, a maximum temperature may be stored in field 322, and a cooling rate may be stored in field 324. The total duration of annealing can be stored in field 326. For film deposition, the type of material to be deposited (such as copper, aluminum, nitride, oxide, etc.) can be stored in the field, and the thickness of the film (if not present, or 500 kPa, 1000 kPa, etc.) stored in another field. Can be. For ion implantation, the ion type can be stored in the field, and the implantation depth (if not present, or 250 μs, 1500 μs, etc.) can be stored in the field. For diffusion processes, the diffusion depth can be stored in the field.

Source data for the test substrate, including ingot identification and ingot section identification data, may be stored in field 370. The results of the crystal lattice defect or metallic fouling test may be stored in field 371.

This type of information about the test substrates may be stored in the database 150 as a function of substrate source, substrate inspection results, and / or details of processes performed on a particular test substrate, including high temperature annealing processes. It may be used by the system 100 to facilitate the selection of an appropriate regeneration method, such as crystal lattice defect reduction processing for a test substrate. Of course, additional fields such as field 327 for these and other types of processes, inspections, and substrate history, for use in selecting an appropriate regeneration process, including crystal lattice defect or metallic contaminant reduction treatments, may be used. There is additional information that can be stored.

As mentioned previously, in the examples of FIGS. 4 and 9, data is preferably stored for each manufacturing-processing step performed on the test substrate. Thus, history and inspection data storage (block 312) continues until all history and inspection steps (block 330) are stored in the database 150. Substrate data may be " date stamped " by storing the date the substrate processing history and inspection data are stored in database 150 of field 334 (block 332). It is contemplated that processing history or inspection data may not be available for all test substrates to be reproduced. If the substrate data is not available (block 310), the system 100 may proceed to store the appropriate indication such as "UNAVAILABLE" in the appropriate field of the record for the test substrate and proceed with the date stamp operation ( Block 332).

If the source and processing history and inspection data are stored in the database 150 for test substrates identified for playback (block 334), the system 100 terminates the test substrate history and inspection database storage operations (block 336). ), As described below, one may begin to determine the appropriate regeneration method for each test substrate of database 150. If not, the operations of FIG. 9 can be repeated and create a record for each remaining test substrate (block 302) to store test substrate processing history data for each remaining test substrate as described above.

FIG. 10 shows the database shown in FIG. 4 for each test substrate of database 150 using a regeneration algorithm engine to identify suitable regeneration methods, such as appropriate crystal lattice defects or metallic contaminant reduction treatments in this example. An example of operations 350 that may be performed to process a test substrate history and inspection database such as 150 (block 154 of FIG. 2) is shown in greater detail. The operations of FIG. 10 are performed after one or more test substrates are identified in a manner similar to that described above in connection with FIG. 7 and after processing history, source history, and inspection data are stored in the database 150 for such test substrates. desirable. Thus, after the individual test substrates have been identified by the reader, a regeneration method may be selected and stored in the test substrate history database 150, or alternatively, the batch of test substrates may be for example the operations of FIG. After the substrate data has been stored for each of the test substrates of the batch of test substrates, for example by the operations of FIG. 9, the reproduction methods are selected for the batch of test substrates, on a separate basis. And may be stored in a test substrate history database.

In order to determine if the crystal lattice defect reduction process is appropriate, if appropriate, to check the recording (300a, 300b ... 300n) and inspection of the test substrate history to select the appropriate crystal lattice defect or metal contamination reduction process for the test substrate. Database 150 is read for a particular test substrate (block 360). The recording portions 300a, 300b ... 300n may be processed in the specific recordings 300a, 300b ... 300n or appropriate recording portions selected for the specific test substrate. The readouts 300a, 300b ... 300n are examined to determine whether the inspection results for the test substrates associated with such databases indicate the possibility of crystal lattice defects or metal contaminants. If determined to indicate the likelihood of contaminants, a crystal lattice defect or metal contaminant reduction treatment is assigned based on the inspection results and, if appropriate, the substrate processing history (block 364), and a crystal lattice defect or metal contaminant reduction treatment is such. It is stored in the field 392 of the recording unit for the test substrate.

System 100 preferably includes a database, such as database 380 of FIG. 1, in which detailed instructions may be stored for a number of different regeneration processes, including crystal lattice defect or metal contaminant reduction processing. Thus, the database 380 may include a number of records, for example, in which each record details a title or other brief description of the playback process of the field 384, an identification code of the field 386, and various steps of the playback process. A recorder 382a ... 382n may be included for each playback process including fields 390. In this embodiment, the regeneration processes may include a collection of methods for regenerating a particular type of test substrate having a particular type of crystal lattice defects. It will also be appreciated that the detailed processing history stored for each test substrate to be regenerated can easily be modified to increase the efficiency of regeneration processes.

Once the desired defect or contamination reduction regeneration process is selected from the regeneration process database 380 for a particular test substrate, based on the inspection results and, if appropriate, the processing history stored in the database 150 for the test substrate, The identification code is stored in a field 392 in the records 300a, 300b ... 300n of the database 150 associated with the particular test substrate (block 364).

If the inspection results do not indicate suitable crystal lattice defects or metal contaminants, then the readouts 300a, 300b ... 300n indicate that the source data comprising the source ingot section from which the substrate was fabricated is not suitable for the possibility of lattice defects or contaminants. It may also be examined to determine if it is indicated (block 400). If so, the lattice defect or metal contaminant reduction process is allocated based on the substrate source data and, if appropriate, the substrate processing history (block 402) and stored in field 392 of the record for such a test substrate.

If the substrate source data does not indicate suitable grating defects or metal contaminants, the readouts 300a, 300b ... 300n may also be examined to determine if the substrate processing history indicates the likelihood of grating defects or metal contaminants. have. If so, the crystal lattice defect or metal contaminant reduction process is assigned based on the substrate processing history (block 412) and stored in field 392 of the record for the test substrate.

The replay algorithm engine of FIG. 10 examines each record of the test substrate identified for regeneration and the selection of an appropriate regeneration process for each such test substrate and processes all (blocks 420, 422) test substrate history writers. Storage of the reproduction process identification code into the associated record for such a test substrate.

FIG. 11 may be performed for physical classification (block 160, FIG. 2) and separation into categories of test substrates using the identified playback methods and may be stored in the test history database 150 shown in FIG. One embodiment of operations 430 that may be shown in detail. The operations of FIG. 11 preferably include one or more test substrates identified and inspected in a manner similar to that described above with respect to FIG. 7, test substrate processing history and the examined inspection database, and a suitable regeneration process disclosed above with respect to FIG. It is performed after being stored in the database 150 for these test substrates in a similar manner. The test substrate can be identified and inspected, and the regeneration process and test substrate selected for the test substrate can be sorted and separated before processing the next test substrate. Alternatively, test substrates can be identified and inspected one batch at a time, and regeneration processes can be selected one batch at a time for each test substrate in the batch, and the test substrates are then sorted and separated one batch at a time. .

In order to classify the test substrates for regeneration, the test substrate may be read by an identification code by which the test substrate can be read by an appropriate reader 126 (block 450, FIG. 11) and by an appropriate robot 172 (FIG. 5). May be recovered from cassettes or other reservoirs 118a, 118b, ... 118n. In some applications, the test substrate can be inspected for crystal lattice defects at this time. Using the read identification code, the recording sections 300a, 300b ... 300n of the test substrate history database 150 are read (block 452), and the test substrate transfers the test substrate to the appropriate reproducing cassette 118a ... 118n) or other reservoir to sort by robot 172. In one embodiment, each cassette 118a... 118n may be associated with one particular type of regeneration process, including one particular type of crystal lattice defect or metal contaminant reduction treatment.

Thus, for example, one cassette can be used to store test substrates with COP defects, which will undergo appropriate annealing treatment for such COP defects. Other cassettes can be used to store test substrates with OISF defects, which will undergo proper annealing treatment for such OISF defects. The other cassette can accommodate test substrates that require defect handling or the like for substrates having a combination of defects. In the illustrated embodiment, the identification code of the playback process intended for each cassette is sorted in the field 464 of the cassette database recorder 210a ... 210n associated with the particular cassette.

In order to identify the appropriate destination cassettes 118a ... 118n for the test substrate being processed by the robot 172, the identification code of the reproducing process selected for the test substrate is added to the test history database recorder for the test substrate. Read from field 392 and the identification code for the cassette selected for the playback process is read from cassette database 120. Robot 172 places the test substrate in an open slot of the cassette identified for the regeneration process. The identification code of the destination cassette on which the test substrate is located may also be stored in field 472 of the test history database recorder 300a ... 300n for a particular test commercial. Similarly, data identifying which cassette the test substrate is located on and the slot number of the cassette may be stored in the cassette database 120. For example, the identification code of the test board may be stored in the appropriate record of the cassette database 120 for the destination cassette in the appropriate test board identification code for the slot number field 264 of the slot of the destination cassette in which the test board is stored. have.

After placing the test substrate in the destination cassettes 118a ... 118n, a query (block 476) can be made to all test substrates scheduled for regeneration. If not, a query (block 478) may be made as to whether the last destination cassette is full of sorted test substrates. If so, the data in the database 120 for the cassette can be “data stamped” by storing the data, and the test substrate and playback data are stored in the database 120 for the cassette in field 479. do.

In addition, labels can be printed (block 480) and attached to cassettes. 12 shows one embodiment of such a cassette label 500. Cassette label 500 may preferably be computer generated, but may be generated in any suitable manner. System 100 may print label 500 such that label 500 may include various useful information. For example, the label of FIG. 12 identifies the cassette identification code of portion 502, and the playback process selected for each of the test substrates stored in the cassette is identified in portion 504. The playback process may be identified by a description title or an identification code or both, and may further include a description of the steps of the playback process. In general, other information that may be printed on the label 500 at a portion at 506 may include the date when the test substrates were placed in the cassette, the identity of the owner or other customer information of the test substrates, the identity of the company that sorted the test substrates, and Includes a proof of identity of the supplier, which is designed to carry out the regeneration process on the test substrates of the cassette. In addition, a list of all test substrates stored in the cassette may be listed on the side of the label in another portion 508. This list may include the identification code of each test board and the slot number in which the test board is stored.

If not all the test substrates have been stored, the robotic processing system can identify another test substrate (block 450), classify it by the regeneration process, and place it in the appropriate cassette for its regeneration process (the block ( 452-470)). Once all test substrates have been sorted (block 476), cassette labels can be printed for all remaining cassettes (block 510), and the remaining cassettes have not yet been labeled in a manner similar to that disclosed in FIG. 12 above. Things. Cassettes containing sorted test substrates and retaining cassette labels are ready to be processed according to the playback process identified on each cassette label (block 512).

FIG. 13 generally illustrates one embodiment of operations that may be performed by a playback operator at 590. According to additional aspects, prior to actually executing the regeneration processes on the test substrates, the verification process (block 600) may be executed on the test substrate by the regeneration operator as shown in FIG. Such verification may include verifying test board identification codes, cassette identification codes and playback process identification codes described in more detail in FIG. 15, discussed below.

Subsequent to verification, additional identification codes may be selectively written on each test substrate using some or all of the test history database 150. The information from the database 150 can be delivered to the playback operator by a network connection, for example by a floppy disk or an optical medium or a portable or removable medium such as the Internet. FIG. 16 shows one embodiment of a test substrate 130 having a first identification code 240, which is written by the substrate manufacturer. Using the test substrate history database, the second identification code 610 may be written onto the test substrate by, for example, a replay operator. The second identification code disclosed in FIG. 17 may include various alphabetic characters and other symbols that are visible to the human eye, readable by the vision of the machine, or both. For example, the additional identification code may include identification symbols 612 of a playback process that the test substrate will undergo processing such as COP processing, BMD processing, COP / OISF processing, and the like.

The second identification code 610 is a field 614 of symbols identifying a playback processor, a field 616 of symbols identifying a date on which the second identification code 610 was added or a date on which the playback processor was performed, and a test. It may further include a field 618 of symbols that uniquely identify the substrate. Field 618 may be the same as code 240 written by the board manufacturer or new test board identification code generated by the playback processor.

Subsequent to verification of the substrate identity and regeneration process (block 600), and following the writing of the second identification code (block 602), the test substrate may be regenerated according to the regeneration process identified for the particular test substrate. (Block 630. As previously mentioned, the regeneration process, based on the recorded processing history of a particular test substrate, not only increases the efficiency of the regeneration process but also eliminates unnecessary thinning of the regenerated test substrates. It may be chosen in a way that can be reduced.

15 shows embodiments of operations 640 that may be performed by a replay operator to verify the identity of each test substrate prior to regeneration of the test substrate. As mentioned previously, the test substrates may be stored in cassettes, such as cassettes 118a... 118n where the test substrates are sorted by the regeneration process type. The replay operator may have a computerized system similar to the system 100 shown in FIG. 1. To verify that the test substrates were properly classified and assigned to the proper regeneration process, the robot 172 removes the test substrate from the cassettes 118a ... 118n (block 650) and the scanner 126 tests The test substrate is scanned (block 652) to read test substrate identification codes written on the substrate or otherwise located. Using the board identification code, the relevant portions of the test history database 150 delivered to the replay operator are used to obtain a test board (field 472) and a regeneration process (field 392) assigned to the test board. Can be retrieved for the identification code (field 306, FIG. 4). The test board identification code, the reproducing process and the cassette identification code of the test board are sent to the cassette from which the test board is retrieved to confirm that the test board has been sent to the reproducing operator of the appropriate cassette having the appropriate reproducing process identified for the cassette and the test board. The corresponding information printed on the attached labels 182a... 182n may be compared. In addition, this information can be compared to what is included in any printed reports, such as a substrate ID report (FIG. 8), which may involve cassettes of test substrates for the playback operator.

In some embodiments, the cassette database 120 or the test of FIG. 3 sent to the playback processor confirms that the test substrate has been sent to the playback operator of the appropriate cassette with the cassette and the appropriate playback process identified for the test substrate. It may be desirable to write to a database such as history database 150 (block 656). After replacing the test substrate (block 660), another test substrate can be removed from the cassette and verified as discussed above. Once all the test substrates of the cassette have been verified, another label can be printed (block 664) and attached to the cassette indicating that the identity of the test substrates and the designed regeneration process type have been verified for each test substrate of the cassette. Alternatively, a label, such as label 500 affixed to the cassette, as it is transported to the regeneration operator may appear to indicate verification. The remaining cassettes can be verified as disclosed above with respect to FIG. 15.

Following verification, additional identification codes can be written on the cassettes as disclosed above. Test substrates of each verified cassette can then be reproduced in the manner specified by the label accompanying the cassette 500 or the test substrates. Various regeneration steps are known to those skilled in the art. In addition, tools for performing regeneration steps are known to those skilled in the art. For example, polishing steps may be performed by an Applied Materials Reflection Tool, and cleaning steps may be performed by an Applied Materials Oasis Tool. Other tools by Applied Materials Inc. and other manufacturers for other regeneration processes are likewise known to those skilled in the art.

The disclosed techniques of regenerating test substrates and preparing test substrates for regeneration may be implemented as a method, apparatus, or article of manufacture using standard programming and / or engineering to manufacture software, firmware, hardware, or any combination thereof. . An exemplary embodiment of a controller 300 that can control sorting, regeneration and inspection processes is shown in FIG. 18. Controller 300 includes a computer that includes a central processing unit (CPU), such as, for example, a Pentium processor from Intel Corporation, located in Santa Clara, California, coupled to memory 308 and peripheral computer components. Memory 308 may include removable storage medium 310, such as a CD or floppy drive, non-removable storage medium 312, such as a hard drive, and random access memory 314. The controller 300 may further include a plurality of interface bars including analog and digital input output boards, interface boards, and motor controller boards. The interface between the operator and controller 300 may be via display 316 and light pen 318. The light pen 318 detects light emitted by the monitor display 316 with an optical sensor at the tip of the light pen 318. To select a particular screen or function, the operator touches a designated area of the screen on the monitor 316 and presses a button on the light pen 318. Typically, the color of the touched area changes or a new menu is displayed to ensure communication between the user and the controller 300.

In one version, controller 300 includes associated databases stored in memory 308 and computer-readable code 320 on non-removable storage medium 312 or removable storage medium 310, for example. do. Computer readable code 320 is generally a process control code for operating robot 322 to transfer substrates from a furnace or microwave chamber to cassettes, a heater used to heat the substrate and may be an electrical resistance heater or a microwave heater. 324, a sensor 326 that detects or inspects substrates to determine defect and metal contaminant types and surface concentration levels, gas flow controls 328 to maintain the pressure of the gas in the substrate processing chamber, and the substrate and Reader 330 for reading or positioning identification information on the cassettes. Computer-readable code 320 may be written in conventional computer-readable code 320 such as, for example, assembly language, C ++, or Fortran. Appropriate program code is entered into a single file or multiple files using conventional text editors and stored or embedded in a computer-usable medium of memory 308. If the entered code text is a high level language, the code is compiled and the resulting compiler code is then linked with the object code of the precompiled library routine. To execute the linked, compiled object code, the user invokes the object code, causing the CPU 306 to read and execute the code to execute the tasks identified in the program.

The computer-readable code stored in the controller 300 obtains, for example, for each read test substrate, stored test substrate data describing each read test substrate from a database, and for the read test substrate. Program code for assigning a crystal lattice defect reduction process associated with stored test substrate data to each read test substrate. In addition, the program may, for each read test substrate, obtain a stored test substrate data describing each read test substrate from a database, and assign an assigned metal contamination reduction process, or even an associated copper reduction process. Code may also be provided.

The term "manufactured article" as used herein refers to hardware logic (eg, integrated circuit chip, programmable gate array (PGA), application specific integrated circuit (ASIC), etc.) or magnetic storage media (eg For example, computer readable media such as hard disk drives, floppy disks, tapes, etc., optical storage devices (CD-ROMs, optical disks, etc.), volatile and nonvolatile memory devices (e.g., EEPROM, ROM, PROM). , Logic, code, logic, etc.) that is executed in RAM, DRAM, SRAM, firmware, programmable logic, etc. Code of the computer readable medium is accessed and executed by the controller 300. The program code on which the preferred embodiments are executed may further be accessible via a transmission medium or from a file server on a network. In such cases, the article of manufacture on which the code is executed may include a transmission medium, such as a network transmission line, a wireless transmission medium, a signal propagating through space, a radio wave, an infrared signal, and the like. Thus, the "article of manufacture" may include the medium in which the code is embodied. In addition, an "article of manufacture" may include a combination of hardware and software components in which code is embodied, processed, and executed. Of course, those skilled in the art will recognize that many modifications can be made to this configuration without departing from the scope of the present invention, and that the article of manufacture may include its information bearing medium known in the art. There will be.

In the disclosed implementations, certain aspects of regeneration preparation and processing are included in a computer for direct processing of test substrates. In alternative implementations, the readiness preparation and processing executions may be any type of electronic device that communicates with other devices, such as portable computers, palmtop computers, laptop computers, network switches or routers, communication devices, network appliances, wireless devices, and the like. Can be implemented.

3, 4, 8 and 14 show specific information maintained in a database stored in computer memory. In alternative implementations, additional or different types of information may be maintained. The operations shown in FIGS. 2, 7, 9, 10, 11, 13 and 15 show certain events occurring in a particular order. In alternative embodiments, certain actions may be executed, modified, or removed in a different order. In addition, steps may be added to the above disclosed logic and may also be tailored to the disclosed embodiments. The operations disclosed herein may occur sequentially, or certain operations may be processed simultaneously. In addition, the operations may be executed by a single processing unit or by distributed processing units. The operations disclosed as being performed by the manufacturer may also be performed by the playback operator. Conversely, operations disclosed as being performed by a replay operator may be performed by a producer.

There are various known crystal lattice defects that may appear on the surface of the substrate. These defects include crystal-originated particles (COP) at the substrate surface, bulk micro-defect (BMD) concentrations at the substrate surface, and oxidation-induced stacking (OISF). fault). These defects can manifest themselves in various patterns, including ring shaped patterns, often referred to as "ring marks", often disc shaped patterns, referred to as "red lines" or COP patterns. It is believed that the ring and disc shaped scattered defect patterns result from silicon crystal ingot growth and can be improved from the high temperature annealing process experienced in the manufacturing facility.

Table 1 below describes a number of embodiments of crystal lattice defect reduction processes that are believed to reduce or reduce defects in accordance with the type and combination of defects and defect patterns currently believed to appear adjacent to the substrate surface. . Such treatments include basic annealing heating treatments with or without one or more auxiliary gases to facilitate removal of defects. The annealing temperature may be substantially constant or may be raised in a controlled manner. In addition, cooling can be controlled such that the temperature is lowered in a controlled manner. A maximum period of processing can be provided. Substrates can also be processed in batches. Spacing of substrates, such as either vertical or horizontal spacing, may also be provided. Parameters may be selected to minimize or reduce slip band generation.

Table 1

Fault (s) Temperature Temperature rate (℃ / min) Auxiliary Chemicals Cooling rate (℃ / min) Duration in seconds Batch substrate COP 900 15 N2, Ar or H 20 30 seconds 25-50 per load BMD 950 15 same 20 30 same OISF 1050 15 same 20 30 same COP and BMD 950 15 same 20 30 same COP and OISF 1050 15 same 20 30 same BMD and OISF 1050 15 same 20 30 same COM, BMD, and OISF 1050 15 same 20 30 same

In another aspect of the invention, a substrate identification process is used for substrates contaminated with metal contaminants that are separated from other substrates. Each read test substrate is then assigned to the metal contamination reduction process according to the stored test substrate data for each read test substrate. Multiple test substrates read may also be classified into multiple groups, with each test substrate in a group having a common assigned metal contamination reduction treatment. These processes are performed in the same manner as for the grid defect identification processes disclosed above.

Each read test substrate in the group has a common identified metal contaminant and / or contaminant level, for example, the common identified metal contaminant may be copper, or may have a detectable surface contaminant level greater than 10 ppb. It can be specified as having copper. The stored test substrate data may further include data identifying manufacturing-processing steps that the read test substrate undergoes, including deposition and annealing processing. Thus, a plurality of read test substrates are classified into a plurality of groups, each group of test substrates being associated with (i) a common identified processing step, and (ii) a common assigned metal contaminant or minimal metal. Has contaminant levels. Each group of read test substrates having common levels or contaminant types can be sorted in the cassette, and the cassette is labeled with an indication indicating the metal contaminant reduction process associated with the group.

The read test substrates can also be inspected to identify the metal contaminant level of the test substrate, and test substrate data describing the results of defect inspection on the substrate is stored in a database.

In the inspection process, multiple substrates are tested to detect the concentration level or type of metal contaminants on the surface. For example, substrates with specific metal contaminant levels in excess of 10 ppb can be determined as high levels of contaminants and separated from other substrates to remove metal contaminants. Preferably, substrates having such high levels of metal contaminants are separated from other substrates to prevent contamination of other low level contaminated or uncontaminated substrates with metal contaminants extracted from highly contaminated substrates. Is played as an enemy.

Metal contaminant levels of selected substrates can be detected by conventional measurement techniques, such as Auger spectroscopy or electron microscopy scanning methods. Metal contaminant levels on each substrate also measure trace components such as inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), and graphite furnace atomic absorption spectroscopy (GFAAS). Can be detected using elemental analysis techniques used for the purpose.

ICP-MS is a preferred testing method because of its sensitivity and multi-element properties. In the ICP-MS method, a gas or plasma composed of ions, electrons and neutral particles is formed of argon. Plasma is used to atomize and ionize elements found on the surface of the substrate. The resulting ions then identify the isotopes of the elements by the intensity of a particular peak of the mass spectrum proportional to the amount of isotope (element) of the original sample and its mass-to-charge ratio (m / e). A high vacuum mass spectrometer passes through a series of opening cones. Suitable ICP-MS devices are available from Agilent Tech. 7500 series from Inc.

Substrates determined to contain sufficiently high levels of metal contaminants are separated from other substrates for processing in the device, which are dedicated or specifically marked for treating metal contaminants. Each metal contaminant may have its own regeneration treatment device line, or many different metal contaminants may be regenerated in the same device line when cross-contamination of the metal contaminants does not affect subsequent removal steps. For example, the separation of certain metal contaminant regeneration lines, such as copper and non-copper regeneration lines, is used to prevent cross contamination. Even when separating copper-containing substrates, care must be taken to prevent substrate-to-substrate contacts in order to reduce the possibility of cross-contamination of the substrates in the batch.

Also, substrates suspected of containing metal contaminants that cannot be detected can be heated and quenched to assist in the detection of metal contaminants. Metal contaminants, such as copper impurities typically deposited or dropped on the substrate surface, often penetrate deep into the bulk of the substrate during subsequent processing or cleaning steps performed on the substrate. When the substrate is a silicon substrate, bulk silicon often contains an unacceptably high level of copper and the surface contains only traces of copper that are virtually undetectable. Copper has a particularly low diffusion coefficient in silicon of 1 x 10 ^-4 cm ² / sec and rapidly diffuses in silicon even at low temperatures, leading to device failure. Copper diffusion can even occur at room temperature, so after several months in the reservoir, copper in bulk silicon diffuses from the surface to contaminate the fabricated device.

Moreover, even if the surface metal contaminant levels can be detected, the surface can be heated to diffuse metal species from the bulk substrate below the surface to the surface, thereby increasing the surface concentration of the species to prevent their removal. To facilitate. For example, copper contamination in the bulk of a silicon substrate can be increased and detected before shipping many reclaimed substrates, or even by heating in a substrate manufacturing line.

In one embodiment of the regeneration process, a substrate comprising metal contaminants such as copper-containing materials is detected and removed in a batch of other substrates for copper removal. Copper-containing impurities may include elemental copper or copper compounds. The copper impurity-containing substrate is heated to energize copper species in the substrate, allowing diffusion of copper paper from the bulk to the substrate surface. In one method, the substrate is heated in a furnace and the furnace may be an electric resistance heating furnace or an induction heating furnace. In the furnace, a very large number of substrates can be processed simultaneously to increase efficiency, and handling and environmental conditions must be chosen to prevent further contamination of the substrate. The substrate is heated for a period of time to a temperature high enough to direct metal contaminants such as copper-containing zones to the substrate surface. In one version, the substrate is heated to a temperature of at least about 160 ° C, more generally to a temperature of about 240 to about 440 ° C. The temperature is maintained for a time period of at least about 50 seconds, more generally about 60 to about 220 seconds. After the heating step, contaminants diffused to the surface of the substrate can be detected using ICP-MS or other techniques, and surface areas with high levels of contamination can be easily removed.

The heated substrate environment can also be controlled to provide the desired composition of the surface layer of the substrate. For example, the silicon substrate can be heated in an oxygen-containing environment, and the surface layer of the silicon substrate is replaced with a silicon dioxide layer, which can be more easily removed by a chemical stripping process. Thus, in one version, the substrate can be heated in an oxygen-containing environment such as air or oxygen gas. However, the silicon substrate may be heated in a homogeneous atmosphere, such as an argon atmosphere, so that the surface level may remain as a silicon layer. Metal contaminants that diffuse to the surface are entrapped in the surface layer anywhere in the composition of the surface layer.

After heating, the substrate is quenched, ie rapidly cooled, at an extinction rate high enough to obtain a surface concentration level of metal contaminants higher than the original surface concentration level. It should be noted that the time / temperature at which the substrates are heated, and the rate at which they are cooled, are all important for controlling the diffusivity of metal contaminants. Heating to too low a temperature will cause a slight diffusion of metal contaminants or no diffusion at all. In addition, if the substrate is not quickly quenched or cooled, the metal contaminants diffuse backward from the surface into the bulk of the substrate. Thus, for example, the substrate is heated and quickly quenched to obtain a second surface concentration level of metal contaminants higher than the first (circle) surface concentration level. For example, the second surface concentration level can be achieved at least about 20% higher than the first surface concentration level, or even at least about 50% higher than the first surface concentration level. For example, in one version that can be used when the surface concentration that can be detected is very low, the substrate is heated to temperature and for a period of time to obtain a surface concentration level at least about three times higher than the original surface concentration level of the metal contaminant. It is quickly extinguished. Generally, the first or original surface concentration level of metal contaminants such as copper at the surface is less than about 10 ppb. The substrate is heated and quenched to increase the surface copper concentration to at least about 50 ppb.

The substrate quickly quenches at an average quench rate, which is the quench rate obtained during the cooling time period. For example, the average extinction rate can be determined by subtracting the final cooled temperature from the temperature at which the substrate is heated and dividing by the time in seconds. Because the cooling rate is often nonlinear, the average extinction rate is a more accurate measure. In one version, the substrate is cooled to room temperature at the temperature described above. For example, the average extinction rate is appropriately at least about 3 ° C./sec, preferably at least about 5 ° C./sec. For example, heating the substrate to a temperature of at least about 240 ° C. can cause the substrate to quench to room temperature at that temperature in about one minute. In one method, the substrate is quenched by exposing the substrate to liquid nitrogen vapor.

In another version, the substrate is heated by applying microwave radiation to the substrate. Microwave Radiation ... Microwave heat generators are generally less expensive to operate and set-up and do not require a specific electrical power line such as a furnace. In addition, since microwave power is absorbed directly by the copper-containing impurity species, it is possible to heat the substrate more efficiently using electric power in a short time. Copper species are directly excited by microwave energy rather than by conductive heat transfer. The microwave power is preferably applied at a power level of at least about 500 W, more typically between about 1000 W and about 2000 W, even about 1500 W. The microwave power is applied for a time period of at least about 40 seconds, more generally between about 95 seconds and about 135 seconds.

The effect of heating by microwave power on the copper surface concentration of the two substrates is shown in Table 2 and measured by the ICP-MS method. In this experiment, the substrate containing copper was an 8 "diameter substrate and was contaminated with copper in the bulk of the silicon substrate. The second substrate was a 6" diameter silicon substrate and was not contaminated with copper. Initially, after 30 seconds of heat treatment with microwave energy, both substrates had a low copper surface concentration and were measured by ICP-MS. The contaminated substrate had about 1.1 parts per billion (copper) of copper on the surface and the uncontaminated substrate had about 0.123 ppb of copper on the surface. However, after 60 seconds of heat treatment with 1550 W microwave energy, the contaminated substrate had a high copper surface concentration of about 223 ppb copper at the surface, and the uncontaminated substrate did not change significantly to 0.095 ppb copper at the surface. . Thus, in contaminated substrates, the copper surface concentration increased 200 times after 60 seconds of heat treatment with microwave energy. This marked increase in surface concentration allows contaminant copper to be easily removed from the substrate by removal of the surface layer with high copper concentration. It also enables easier detection of copper contamination in the substrate using the ICP-MS method.

Copper contamination substrate Non-pollution substrate 8 ''-copper-30 seconds 8 ''-copper-60 seconds 6 ''-copper-30 seconds 6 ''-copper-60 seconds M.W. ppb (μg / L) 10⌒10 atoms / cm ² ppb (μg / L) 10⌒10 atoms / cm ² ppb (μg / L) 10⌒10 atoms / cm ² ppb (μg / L) 10⌒10 atoms / cm ² Na 22.990 0634 1.585 4.934 12.338 0.201 0.894 0.237 1.054 Mg 24.305 0564 1.334 6.042 14.291 0.135 0.568 0.213 0.896 Al 26.982 1.231 2.623 1.642 3.498 1.383 5.238 1.445 5.473 K 39.000 0.186 0.274 0.450 0.663 0.114 0.299 0.226 0.592 Ca 40.078 0.394 0.56590 0.736 1.056 0.232 0.592 0.425 1.084 De 55.847 0.471 0.485 0.917 0.944 0.192 0.351 0.176 0.322 Cu 63.546 1.119 1.012 257.800 233.218 0.123 0.198 0.095 0.153 Ni 58.690 0.148 0.145 0.145 0.142 0.135 0.235 0.129 0.225 Cr 52.000 0.012 0.013 0.010 0.011 0.006 0.012 0.004 0.008 Zn 65.390 0.196 0.172 0.065 0.060 0.116 0.181 0.105 0.164 Co 59.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Metallic Contaminants Included in the Substrate Surface After the heating and quenching process steps to raise the paper substrate surface, the metal contaminants are removed from the substrate surface using one or more different removal methods. In one removal process, the substrate surface may be ground and polished by conventional chemical mechanical polishing (CMP). A typical CMP apparatus includes a polishing head that vibrates and pressurizes a substrate against a polishing pad while an abrasive particle slurry is supplied between the substrate and the polishing pad in accordance with the selected slurry recipe. The polishing pad typically has a plurality of layers made of a polymer, such as polyurethane, and may include a filler for additional dimensional stability, and an outer resilient layer. Typically, polishing pads for oxide polishing are relatively hard and incompressible pads and have surface grooves for facilitating the distribution of slurry solution and incorporating particles. Generally, the size of the polishing pad is at least several times larger than the diameter of the substrate, and the substrate is off-centered on the polishing pad to prevent polishing of non-planar surfaces on the substrate. The polishing slurry may include deionized water in which abrasives are suspended, such as, for example, colloidal silica, aluminum oxide, silicon carbide, or even diamond particles. Both the pad and the substrate can be programmed to rotate at different rotational speeds and directions depending on the process recipe, and they are generally rotated simultaneously with axes of rotation that are generally parallel to each other but not collinear to prevent the taper from grinding into the substrate. .

The CMP process removes the surface layer of the substrate with a thickness that depends on the grinding slurry, polishing pad configuration, polishing time, polishing pressure, and other such variables. CMP polishing is known as a result of both chemical and mechanical effects-for example, chemically changing layers are repeatedly formed on the surface of the material being polished and then polished off. In polishing a heated silicon substrate in an oxygen-containing environment, the silicon dioxide surface layer contaminated with metal contaminants such as copper is removed by a CMP process. Typically about 2 microns to about 20 microns, more generally about 10 microns thick, are removed from the substrate.

Other surface removal processes use chemical strippers to remove the surface layer of the substrate with higher metal contaminant concentrations. Chemical strippers may consist of acids or bases, which are selected to dissolve the surface layer. Typically, when a substrate, including a silicon substrate, is heated in an oxygen-containing environment such as air, the surface layer turns into a silicon dioxide layer. Thus, metal contaminants diffused to the surface are incorporated into the surface silicon dioxide layer. In these layers, a suitable chemical stripping solution comprises HF (hydrofluoric acid) solution, and the HF solution comprises HF diluted in HF concentration of 30-40% in water, for example. However, if the silicon substrate is heated in an inert atmosphere, the surface layer consists of silicon atoms incorporating metal contaminants, which layer can be removed by a suitable acidic solution.

In another version, while the substrate is still heating, hydrogen-halogen gas is provided in the substrate environment. The hydrogen-halogen gas contains hydrogen atoms and halogen atoms in atomic or compound form and is selected to chemically corrode the surface layer of the substrate containing contaminants. For example, if the substrate surface contains silicon contaminated with metal contaminants such as copper, the hydrogen fluoride gas can be used to chemically react with the silicon to form silicon fluoride and metal contaminant fluoride vapors, and the metal contaminant fluoride vapor It can be removed in a substrate environment. Hydrogen-halogen gas is provided for a certain flow rate and for a period of time to substantially remove the entire surface level including metal contaminants.

In one example, the hydrogen-halogen gas comprising HCl gas, such as anhydrous HCl gas, is maintained at atmospheric pressure near the substrate. Anhydrous HCl gas reacts with silicon dioxide on the substrate surface to corrode the surface to the desired depth. In one embodiment, the hydrogen-halogen gas may be supplied at a flow rate of about 500 to about 5000 sccm / min, or for example about 3000 sccm / min. In this version, the substrate is maintained at a higher temperature, for example 200 to 500 ° C., and is supported in a quartz furnace (SiO ₂ ) such as, for example, a tubular furnace that does not react with HCl.

Removing the diffused impurities from the substrate surface after heating may also be repeated for several cycles until metal contaminants are no longer detected at the substrate surface. This lowers the metal contaminant concentration in the substrate bulk, such as, for example, copper species concentration, to a level low enough that residual contaminants do not affect subsequent device performance. The number of cycles depends on the depth and concentration of copper species penetrated into the substrate and the heat treatment provided to the substrate. Typically, the number of operating cycles is large enough to lower the concentration of the substrate to less than about 1 x 10 ¹⁰ atoms / cm ² . In one example, the series of heat treatment, quenching, and surface layer removal processes forming one process cycle can be repeated for about 2 to about 10 cycles, or even about 2 to about 5 cycles.

Although exemplary embodiments of the invention have been shown and described, those skilled in the art will be able to devise other embodiments that incorporate the invention and fall within the scope of the invention. For example, other defects or contaminants can be separated, inspected or removed from the substrate using the present methods. As will also be apparent to those skilled in the art, substrates other than the test substrate may also be reproduced by the methods and apparatuses. In addition, terms such as below, above, above, below, above, below, first and second, and other relative or positional terms are shown with reference to exemplary embodiments of the drawings and may be interchangeable. Accordingly, the appended claims should not be limited to the description of the preferred versions, materials, or spatial arrangements disclosed herein for the purpose of illustrating the invention.

Claims (32)

A method of regenerating test substrates used to test semiconductor manufacturing tools, (a) reading a plurality of test substrate identification data from the plurality of test substrates; (b) for each of the read test substrates, obtaining stored test substrate data describing the read test substrates from a database; And (c) assigning each read test substrate a crystal lattice defect reduction process associated with the stored test substrate data for the read test substrate; Including, test substrate regeneration method. The method of claim 1. (a) inspecting each read test substrate to identify crystal lattice defects and storing test substrate data in the database describing the results of the defect inspection on the inspected test substrate; And (b) classifying the read plurality of test substrates into a plurality of groups, each test group of a group having a common assigned crystal lattice defect reduction process; And at least one step of reproducing the test substrate. The method of claim 2, Wherein each read test substrate of a group has a common identified crystal lattice defect. The method of claim 2, Regenerating said each read test substrate of each group using said common assigned crystal lattice defect reduction process. The method of claim 1, Wherein the stored test substrate data includes data identifying a section of an ingot on which the read test substrate is manufactured. The method of claim 5, And wherein said crystal lattice defect reduction process assigned to each said read test substrate is dependent on said identified ingot section from which said read test substrate is manufactured. The method of claim 5, Classifying the read plurality of test substrates into a plurality of groups, each group of test substrates being associated with a common identified ingot section and a common assigned crystal lattice defect reduction process. Test board regeneration method. The method of claim 1. Wherein the stored test substrate data includes data identifying manufacturing process steps that the read test substrate has undergone, including film deposition and annealing processing. The method of claim 8, (a) classifying the plurality of test substrates read into a plurality of groups, each group of test substrates having an associated common identified processing step and a common assigned crystal lattice defect reduction process; And (b) storing each group of read test substrates in a cassette and labeling the cassette of each group with an indicia representing the common crystal lattice defect reduction process associated with the group. And at least one step of reproducing the test substrate. The method of claim 9, Labeling the cassettes of each of the groups with an indication representing the test substrate identification data of each of the test substrates stored in the cassettes of the group. A system for reproducing test substrates used to test semiconductor manufacturing tools, The test boards each have an identification code, the system comprising: (a) a reader for reading the identification code from the test substrate; (b) a controller having a memory for storing a database containing data indicative of the identification code for each test substrate and associated data indicative of crystal lattice defect reduction processing; Wherein the controller obtains, for each of the read test boards, stored test board data describing each read test board from the database, and the stored test board data for the read test data. Program code for assigning a crystal lattice defect reduction process associated with each of said read test substrates. The method of claim 11, Further comprising a robot for transferring the test substrate, wherein the controller controls the robot to transfer the test substrate to a substrate storage container, the substrate storage container having an associated crystal lattice defect reduction process. Substrate regeneration system. The method of claim 11, And further comprising an in-line sensor for inspecting each read test substrate to identify crystal lattice defects, and storing test substrate data in the database describing the results of the defect inspection on the inspected test substrate. Test substrate regeneration system, characterized in that. An article of manufacture for reproducing test substrates used to test semiconductor fabrication tools, the article of manufacture comprising: (a) storing a plurality of test substrate identification data in a database, each said test substrate identification data identifying a particular test substrate of a plurality of test substrates; (b) selecting a crystal lattice defect reduction process from the plurality of crystal lattice defect reduction processes to reproduce each of the plurality of test substrates identified by the plurality of test substrate identification data; And (c) store in the database a plurality of test substrate crystal lattice defect reduction process identification data associated with the stored test substrate identification data to identify a regeneration process selected to regenerate the test substrate; An article of manufacture comprising program code implemented on a computer readable medium. A computer readable medium comprising a computer database of data for reproducing test substrates used to test a semiconductor manufacturing tool, the method comprising: (a) a plurality of test substrate identification data, each said test substrate identification data identifying a particular test substrate of a plurality of said test substrates; And (b) a plurality of crystal lattice defect reduction process data, each crystal lattice defect reduction process data associated with the test substrate identification data; And a computer readable medium. A method of regenerating a test substrate used to test semiconductor manufacturing tools, (a) reading a plurality of test substrate identification data from the plurality of test substrates; (b) for each said read test substrate, obtaining stored test substrate data describing each said read test substrate from a database; And (c) assigning each read test substrate a metal contaminant reduction process associated with the stored test substrate data for each read test substrate; Including, test substrate regeneration method. The method of claim 16, (1) inspecting each read test substrate to identify metal contamination levels of the test substrate and storing test substrate data in the database describing the results of the inspection on the substrate; And (2) classifying the read plurality of test substrates into a plurality of groups, each test substrate of one group having a common assigned metal contaminant reduction process; And at least one step of reproducing the test substrate. The method of claim 17, Wherein each read test substrate of a group has a common identified metal contaminant. The method of claim 18, Wherein said common identified metal contaminant is copper. The method of claim 17, And the stored test substrate data includes data identifying manufacturing process steps that the read test substrate has undergone, including deposition and annealing processing. The method of claim 17, Classifying the read plurality of test substrates into a plurality of groups, each group of test substrates comprising (i) a common identified processing step, and (ii) a common assigned metal contaminant or A test substrate regeneration method characterized by being associated with a minimum contaminant level. The method of claim 21, (1) storing each group of read test substrates in a cassette, and labeling the cassette of each group with an indication indicative of the metal contamination reduction process associated with the group; And (2) regenerating each read test substrate of each group using the assigned metal contamination reduction process to regenerate each read test substrate of each group. And at least one step of reproducing the test substrate. A method of regenerating test substrates used to test a copper fabrication tool, (a) reading a plurality of test substrate identification data from the plurality of test substrates; (b) for each of said read test substrates, obtaining stored test substrate data describing each said read test substrate from a database; And (c) assigning each read test substrate a copper contamination reduction process associated with the stored test substrate data for each read test substrate; Including, test substrate regeneration method. The method of claim 23, wherein (1) inspecting each read test substrate to identify the copper contaminant level of the test substrate, and storing test substrate data in the database describing the test results for the substrate; And (2) classifying the read plurality of test substrates into a plurality of groups, each test substrate of one group having a common assigned copper contaminant reduction process; Test board regeneration method further comprising a. As a method of regenerating a substrate used for semiconductor manufacturing (a) providing a substrate comprising metal contaminants at a first surface concentration level; (b) heating the substrate such that a majority of the metal contaminants of the substrates diffuse to the surface of the substrate; (c) quenching the substrate at an extinction rate high enough to obtain a first surface concentration level of metal contaminant at least about 20% higher than the first surface concentration level; And (d) removing the metal contaminants from the surface of the substrate Substrate regeneration method comprising a. The method of claim 25, wherein step (c) (a) quenching the substrate at an extinction rate high enough to achieve a second surface concentration level at least about 50% higher than the first surface concentration level; (b) quenching the substrate at an average extinction rate of at least about 3 ° C./sec; And (c) quenching the substrate by exposing the substrate to liquid nitrogen vapor. At least one step of the substrate regeneration method characterized in that it comprises. The method of claim 26, Wherein the first surface concentration is less than about 10 ppb and the second surface concentration level is at least about 50 ppb. The method of claim 25, wherein step (b) (a) heating the substrate to a temperature of at least about 160 ° C .; And (b) heating the substrate in an oxygen-containing environment or a hydrogen-halogen gas environment At least one step of the substrate regeneration method characterized in that it comprises. A method of regenerating substrates in semiconductor manufacturing, (a) providing a substrate comprising metal contaminants at a first surface concentration level; (b) applying microwave light to the substrate to heat the substrate such that most metal contaminants of the substrate diffuse to the surface of the substrate; (c) quenching the substrate at an extinction rate high enough to obtain a second surface concentration level at least about 20% higher than the first surface concentration level; And (d) removing the metal contaminants from the surface of the substrate Substrate regeneration method comprising a. The method of claim 29, wherein step (b) (1) applying the microwave light at a power level of at least about 500 Watts; (2) applying the microwave light for a time period of at least about 40 seconds; And (3) applying the microwave light for a time period of about 95 seconds to about 135 seconds At least one step of the substrate regeneration method characterized in that it comprises. A method of regenerating substrates containing metal contaminants in semiconductor manufacturing, (a) providing a substrate comprising metal contaminants at a first surface concentration level; (b) heating the substrate such that a majority of the metal contaminants of the substrate diffuse to the surface of the substrate; (c) quenching the substrate at an extinction rate high enough to obtain a second surface concentration level of the metal contaminant that is at least about 20% higher than the first surface concentration level; And (d) detecting the increased surface concentration level of the metal contaminant Substrate regeneration method comprising a. The method of claim 31, wherein Said step (d) comprises detecting a surface concentration level of said metal contaminant by ICP-MS, said metal contaminant comprising copper.

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